There are different types of ESA decisions that the claimant can challenge, for example:

A decision that they are fit for work and are therefore not entitled to ESA.

A decision that they are in the Work Related Activity Group, not the Support Group.

A decision that they do not have good cause for not returning, or missing the deadline for returning, the medical questionnaire (ESA50 form) or for failing to attend a medical examination and so they have been treated as fit for work and not entitled to ESA.

The application of a sanction or the period a sanction is applied for.